In regard of electrical safety, safety-related precautions must be taken during the charging procedure in order to preclude any risk to the person handling the device and to prevent any material damage. As a result of the electrical connection between the electric vehicle and the charging station, a comprehensive grounded system having alternating and direct voltage/DC components arises from the hitherto ungrounded vehicle power supply of the electric vehicle in connection with a stationary grounded power supply system. Besides an insulation monitoring, a reliably functioning fault-current protective device is therefore of importance. In the following, a fault-current protective device is under-stood to be a generic fault-current protective device having the functions (functional elements): detecting a fault current as a differential current; and evaluating the fault current by monitoring the differential current and having a switching function. Specific structural embodiments (structural designs) of the fault-current protective device are referred to as a type A RCD (residual current device) fault-current protective device according to standard IEC 61008-1//DIN EN 61008-1 (VDE 0664-10) or as a type B RCD fault-current protective device according to standard IEC 62423//DIN EN 62423 (VDE 0664-40).
From the state of the art, the possibility of monitoring the system, which consists of a charging station and a vehicle, via a type A RCD fault-current protective device arranged in the charging station is known, as described in DE 10 2010 028 626 A1, for example. This type A RCD fault-current protective device is capable of detecting alternating fault currents and pulse fault direct currents.
Should the charging station of the electric vehicle be provided with a power outlet or a vehicle coupling according to the series of standards IEC 62196//DIN EN 62196 (VDE 0623), a type B (RCD) fault-current protective device or a type A (RCD) fault-current protective device must be used in conjunction with a suitable device for switching off the supply in the event of faulty direct currents >6 mA according to standards IEC 61851-1 as well as IEC 60364-7-722 (VDE 0100-722) in order to further detect pure fault direct currents (DC fault currents).
The proposed charging stations, which are known from the state of the art and consist of a plurality of electrical component groups having partially redundant functions and requiring extensive wiring and correspondingly large installation spaces, have proven to be disadvantageous as they increase the costs for the production and installation of the charging station.